They will be in it forever until the heavens and the earth endure, except what your Lord will wish; indeed, your Lord accomplishes what He intends.
Verse 98:6 reveals that the hypocritical transgressors who conceal Adhikr—the key to returning to Paradise and the safeguard against all calamities, disasters, diseases, and Hell—and their Mushrik followers are the worst creatures in the land and are destined for Hell. In contrast, verses 98:7-8 describe the believers who embrace Adhikr and actively propagate it throughout the world as the best creatures on earth. They are promised a reward near their Lord: an eternal Paradise with rivers flowing beneath it. They will abide there forever, with their Lord being satisfied with them and them being satisfied with Him. This is the reward for those who fear their Lord.
While it is stated that the inhabitants of Paradise will remain there eternally, the same is not explicitly stated for the inmates of Hell. This distinction arises because those who enter Hell after Trial can be interceded for by the believers from Paradise. Verse 50:35 indicates that for those who testify to the Best Book in the best manner, the inhabitants of Paradise may intercede for weaker disbelievers. Verse 34:23 explains that without Adhikr—the Lord’s Permission—no intercession is accepted. When the terror is lifted from the hearts of disbelievers (who were sent to Hell after Trial), they will ask the believers in Paradise, "What has your Lord said?" The reply will be, "The Truth."
Human devil hypocrites, however, will be cast into Hell without Trial and will remain there eternally, as explained in verse 10:33. See explanation 3:185; 9:80-82; and 11:17-18.